在Spring中有没有数据休息的HATEOAS +分页的简单实现吗？
在Spring中有没有数据休息的HATEOAS +分页的简单实现吗？
提问于 2020-09-19 06:32:08
我已经搜索了几天，关于如何实现一个包含HATEOAS链接的Spring REST API +带有Spring boot和JPA (No spring data rest)的分页，就像这个随机示例：
{
"_links": {
"first": {
"href": "http://localhost:8080/api/albums-list?page=0&size=2&sort=title,desc"
},
"prev": {
"href": "http://localhost:8080/api/albums-list?page=0&size=2&sort=title,desc"
},
"self": {
"href": "http://localhost:8080/api/albums-list?page=1&size=2&sort=title,desc"
},
"next": {
"href": "http://localhost:8080/api/albums-list?page=2&size=2&sort=title,desc"
},
"last": {
"href": "http://localhost:8080/api/albums-list?page=4&size=2&sort=title,desc"
}
},
"page": {
"size": 2,
"totalElements": 10,
"totalPages": 5,
"number": 1
},
"_embedded": {
"albums": [
{
"id": 7,
"title": "Top Hits Vol 7",
"description": "Top hits vol 7. description",
"releaseDate": "10-03-1987",
"actors": [
{
"id": 4,
"firstName": "Janice",
"lastName": "Preston",
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/4"
}
}
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/7"
}
}
},
{
"id": 6,
"title": "Top Hits Vol 6",
"description": "Top hits vol 6. description",
"releaseDate": "10-03-1986",
"actors": [
{
"id": 3,
"firstName": "Laverne",
"lastName": "Mann",
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/3"
}
}
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/6"
}
}
}
]
}
}然而，到目前为止，我发现的解决方案复杂得离谱，或者说样板的数量太多了，例如：https://howtodoinjava.com/spring5/hateoas/pagination-links/页面上的教程没有完整地呈现它，但它要求您创建实体、实体的模型和充满样板的长RepresentationModelAssemblerSupport
我也尝试过这个：https://spring.io/guides/tutorials/rest/，但是嵌套的类(我有一对多/多对一的关系)没有得到HATEOAS的链接：
{
"id": 3,
"nome": "Amazonas",
"uf": "AM",
"cidades": [
{
//no HATEOAS in here
"id": 10003,
"nome": null,
"instituicoes": [],
"uf": "AM"
},
{
"id": 219,
"nome": "Alvarães",
"instituicoes": [],
"uf": "AM"
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/v1/estados/estadoes/3"
},
"estadoes": {
"href": "http://localhost:8080/api/v1/estados/estadoes"
}
}
}我是说，有没有更简单的解决方案？幸运的是，对于分页，PagingAndSortingRepository是有用的，但是同时拥有分页+ HATEOAS，这是一场噩梦。
回答 1
Stack Overflow用户
发布于 2020-09-19 15:23:08
RepresentationModelAssembler是必需的。如果不需要额外的字段，则不需要模型类extends EntityModel<T>。
我的示例实体类是Inventory。
RepresentationModelAssembler。您可以在此处添加更多链接。
@Component
public class InventoryModelAssembler implements RepresentationModelAssembler<Inventory, EntityModel<Inventory>> {
@Override
public EntityModel<Inventory> toModel(Inventory inventory) {
return EntityModel.of(inventory,
linkTo(methodOn(InventoryController.class).get(inventory.getId()))
.withSelfRel());
}
}控制器
@RestController
@RequestMapping("/inventories")
@RequiredArgsConstructor
public class InventoryController {
private final InventoryRepository inventoryRepository;
private final PagedResourcesAssembler pagedResourcesAssembler;
private final InventoryModelAssembler inventoryModelAssembler;
@GetMapping
public ResponseEntity get(Pageable pageable) {
Page<Inventory> inventories = inventoryRepository.findAll(pageable);
return ResponseEntity
.ok()
.contentType(MediaTypes.HAL_JSON)
.body(pagedResourcesAssembler.toModel(inventories, inventoryModelAssembler));
}
}HAL JSON响应。可以在我的HTML doc中找到完整的长响应。下载它并使用浏览器打开。
{
"_embedded" : {
"inventories" : [ {
"carrier" : "SG",
"fltNum" : "001",
"serviceType" : "PAX",
"fltDate" : "2020-01-20",
"fltDow" : 1,
"createdDate" : "2020-06-11T13:21:44.992Z",
"lastModifiedDate" : "2020-06-11T13:21:44.992Z",
"_links" : {
"self" : {
"href" : "http://localhost:8080/inventories/5ee22fe8853b0f45ae5fca27"
}
}
}]
},
"_links" : {
"first" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=0&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"self" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=0&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"next" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=1&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"last" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=1&size=10&sort=fltNum,asc&sort=fltDate,desc"
}
},
"page" : {
"size" : 10,
"totalElements" : 20,
"totalPages" : 2,
"number" : 0
}
}完整的代码在Github中共享。如果我的项目比这个答案更有帮助，请考虑在Github中给它打个星。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/63963571
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